JP2013108190A - Textile manufacturing materials and fibers - Google Patents

Abstract

An object of the present invention is to provide a fiber manufacturing material capable of reducing variations in fiber strength.
A fiber manufacturing material obtained by melt kneading while degassing using a liquid crystal polyester satisfying the following requirements (a) and (b).
(A) Flow start temperature is 280 degreeC or more and 360 degrees C or less.
(B) Using a flow characteristic tester, the melt viscosity measured at 360 ° C. under a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ is 70 Pa · s or less.
[Selection figure] None

Description

  The present invention relates to a fiber manufacturing material and a fiber.

  Liquid crystal polyester is widely used as a material for electronic parts and the like because of its excellent low hygroscopicity, heat resistance, thin-wall formation, and the like. In recent years, taking advantage of such characteristics of liquid crystal polyesters, it has been studied to make liquid crystal polyesters into fibers.

  When the liquid crystalline polyester is made into a fiber, it is generally formed by once melting the liquid crystalline polyester and then stretching it while extruding it through the pores. At this time, the liquid crystalline polyester in the molten state can obtain fine fibers as the viscosity is low, and can be made into a good fiber.

  When a conventional liquid crystal polyester is melted for a long time, the viscosity increases greatly, and it may be difficult to spin thin fibers. However, in recent years, there has been proposed a liquid crystal polyester that can reliably suppress an increase in viscosity even in a molten state and can be easily made into a fiber while maintaining the characteristics (Patent Document 1).

JP 2010-43380 A

  However, the fiber molded using the liquid crystal polyester may vary in strength, and there is room for improvement.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the material for fiber manufacture which can make variation in fiber strength small. Moreover, it aims at providing the fiber which suppressed variation in fiber strength by using such a material.

  As a result of various studies by the present inventors on the above-mentioned problems, it has been found that low molecular weight components such as monomers, dimers, and oligomers remaining in the liquid crystal polyester as a polymerization residue of the liquid crystal polyester contribute to the variation in strength. It was. That is, it was confirmed that in the molded fiber, the fiber strength at the portion where the low molecular weight component does not exist is large, but the strength decreases at the portion where the low molecular weight component exists.

Then, in order to solve said subject, this invention provides the material for fiber manufacture obtained by melt-kneading, using liquid crystalline polyester which satisfy | fills the requirements of following (a) and (b), deaeration.
(A) Flow start temperature is 280 degreeC or more and 360 degrees C or less.
(B) Using a flow characteristic tester, the melt viscosity measured at 360 ° C. under a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ is 70 Pa · s or less.

In the present invention, the liquid crystalline polyester desirably has a repeating unit represented by the following formula (1), the following formula (2), and the following formula (3).
(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X And Y each independently represents an oxygen atom or an imino group (—NH—), and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is independently a halogen atom or a carbon number. (It may be substituted with an alkyl group of 1 to 10 or an aryl group of 6 to 20 carbon atoms.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

In the present invention, the liquid crystal polyester includes a repeating unit represented by the formula (1) in which Ar ¹ is a 1,4-phenylene group, and Ar ² is a 1,4-phenylene group or a 1,3-phenylene group. It is desirable to include a repeating unit represented by a certain formula (2) and a repeating unit represented by the formula (3) in which Ar ³ is a 4,4′-biphenylylene group.

  In the present invention, the liquid crystalline polyester preferably has a content of repeating units containing 2,6-naphthylene groups of 40 mol% or more based on the total content of all repeating units.

  In the present invention, it is desirable to obtain by melting and kneading while deaeration under a vacuum degree of 0.04 MPa or less.

  In the present invention, it is desirable to use an extruder having two or more vent portions and melt and knead while degassing from the two or more vent portions.

  In the present invention, it is desirable to use an extruder equipped with a kneading part on the upstream side of the vent part, and melt and knead while degassing from the vent part.

  Further, the fiber of the present invention is obtained by spinning the above-mentioned fiber production material.

  ADVANTAGE OF THE INVENTION According to this invention, the material for fiber manufacture which can reduce the amount of low molecular weight components by deaerating at the time of melt-kneading, and can make the dispersion | variation in fiber strength small can be provided. Further, by using such a material, it is possible to provide a fiber in which variation in fiber strength is suppressed.

The fiber manufacturing material of this embodiment is obtained by melt kneading while degassing using a liquid crystal polyester that satisfies the following requirements (a) and (b).
(A) Flow start temperature is 280 degreeC or more and 360 degrees C or less.
(B) Using a flow characteristic tester, the melt viscosity measured at 360 ° C. under a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ is 70 Pa · s or less.

  Moreover, the fiber of this embodiment is obtained by spinning the above-mentioned fiber manufacturing material.

The flow start temperature is also called flow temperature or flow temperature, and the temperature is raised at a rate of 4 ° C./min under a load of 9.8 MPa (100 kg / cm ² ) using a capillary rheometer while liquid crystal polyester is used. Is a temperature showing a viscosity of 4800 Pa · s (48000 poise) when extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and is a measure of the molecular weight of the liquid crystalline polyester (Naide Koide, “ “Liquid Crystal Polymer—Synthesis / Molding / Application—”, CMC Co., Ltd., June 5, 1987, p. 95).
Hereinafter, the present invention will be described in detail.

(Liquid crystal polyester)
The liquid crystalline polyester used for the fiber production material of the present embodiment preferably exhibits liquid crystallinity in a molten state and melts at a temperature of 450 ° C. or lower. The liquid crystal polyester may be a liquid crystal polyester amide, a liquid crystal polyester ether, a liquid crystal polyester carbonate, or a liquid crystal polyester imide. The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester using only an aromatic compound as a raw material monomer.

As a typical example of liquid crystal polyester,
(I) An aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid, and at least one compound selected from the group consisting of an aromatic diol, an aromatic hydroxyamine, and an aromatic diamine are polymerized (polycondensed). (II) a polymer obtained by polymerizing a plurality of types of aromatic hydroxycarboxylic acids (III) at least one compound selected from the group consisting of aromatic dicarboxylic acids and aromatic diols, aromatic hydroxyamines and aromatic diamines And (IV) those obtained by polymerizing a polyester such as polyethylene terephthalate and an aromatic hydroxycarboxylic acid.

  Here, the aromatic hydroxycarboxylic acid, the aromatic dicarboxylic acid, the aromatic diol, the aromatic hydroxyamine, and the aromatic diamine are each independently replaced with a part or all of the polymerizable derivative. Also good.

  Examples of polymerizable derivatives of a compound having a carboxyl group such as aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid include those obtained by converting a carboxyl group into an alkoxycarbonyl group or an aryloxycarbonyl group (ester), carboxyl Examples include those obtained by converting a group into a haloformyl group (acid halide), and those obtained by converting a carboxyl group into an acyloxycarbonyl group (acid anhydride).

  Examples of polymerizable derivatives of hydroxyl group-containing compounds such as aromatic hydroxycarboxylic acids, aromatic diols and aromatic hydroxyamines include those obtained by acylating hydroxyl groups and converting them to acyloxyl groups (acylated products) ).

  Examples of polymerizable derivatives of amino group-containing compounds such as aromatic hydroxyamines and aromatic diamines include those obtained by acylating an amino group and converting it to an acylamino group (acylated product).

The liquid crystalline polyester preferably has a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as “repeating unit (1)”), and the repeating unit (1) and the following formula (2) A repeating unit represented (hereinafter sometimes referred to as “repeating unit (2)”) and a repeating unit represented by the following formula (3) (hereinafter sometimes referred to as “repeating unit (3)”). It is more preferable to have.
(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X And Y each independently represents an oxygen atom or an imino group (—NH—), and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is independently a halogen atom or a carbon number. (It may be substituted with an alkyl group of 1 to 10 or an aryl group of 6 to 20 carbon atoms.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.)

  As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned.

  Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, 2-ethylhexyl group, An n-octyl group and n-decyl group are mentioned, The carbon number is 1-10 normally.

  Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group, and the number of carbon atoms is usually 6 to 20. .

When the hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is substituted with these groups, the number is as follows for each group represented by Ar ¹ , Ar ² or Ar ³ . Each of them is usually 2 or less, preferably 1 or less.

  Examples of the alkylidene group include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group, and a 2-ethylhexylidene group, and the number of carbon atoms is usually 1 to 10.

The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid. As the repeating unit (1), Ar ¹ is a p-phenylene group (repeating unit derived from p-hydroxybenzoic acid), and Ar ¹ is a 2,6-naphthylene group (6-hydroxy-2). -Repeating units derived from naphthoic acid) are preferred.

The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid. As the repeating unit (2), Ar ² is a p-phenylene group (a repeating unit derived from terephthalic acid), Ar ² is an m-phenylene group (a repeating unit derived from isophthalic acid), Ar ² Is a 2,6-naphthylene group (a repeating unit derived from 2,6-naphthalenedicarboxylic acid), and Ar ² is a diphenyl ether-4,4′-diyl group (diphenyl ether- 4,4′-dicarboxylic acid-derived repeating units) are preferred.

The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxylamine or aromatic diamine. As the repeating unit (3), Ar ³ is a p-phenylene group (a repeating unit derived from hydroquinone, p-aminophenol or p-phenylenediamine), and Ar ³ is a 4,4′-biphenylylene group. Those (4,4′-dihydroxybiphenyl, 4-amino-4′-hydroxybiphenyl or repeating units derived from 4,4′-diaminobiphenyl) are preferred.

  The content of the repeating unit (1) is the total amount of all repeating units (the mass equivalent amount of each repeating unit (moles by dividing the mass of each repeating unit constituting the liquid crystal polyester by the formula amount of each repeating unit). ) And the total value thereof) is usually 30 mol% or more, preferably 30% or more and 80 mol% or less, more preferably 40% or more and 70 mol% or less, still more preferably 45% or more and 65 mol%. It is as follows.

  The content of the repeating unit (2) is usually 35 mol% or less, preferably 10% or more and 35 mol% or less, more preferably 15% or more and 30 mol% or less, more preferably based on the total amount of all repeating units. It is 17.5% or more and 27.5 mol% or less.

  The content of the repeating unit (3) is usually 35 mol% or less, preferably 10% or more and 35 mol% or less, more preferably 15% or more and 30 mol% or less, more preferably based on the total amount of all repeating units. It is 17.5% or more and 27.5 mol% or less.

  The liquid crystal polyester having such a predetermined repeating unit composition has an excellent balance between heat resistance and moldability. The higher the content of the repeating unit (1), the easier it is to improve the melt fluidity, heat resistance, strength and rigidity. However, if it is too much, the melting temperature and melt viscosity are likely to increase, and the temperature required for molding increases. easy.

  In addition, it is preferable that content of a repeating unit (2) and content of a repeating unit (3) are substantially equal. The ratio between the content of the repeating unit (2) and the content of the repeating unit (3) is expressed as [content of repeating unit (2)] / [content of repeating unit (3)] (mol / mol). The ratio is usually 0.9 / 1 to 1 / 0.9, preferably 0.95 / 1 to 1 / 0.95, and more preferably 0.98 / 1 to 1 / 0.98.

  In addition, liquid crystalline polyester may have 2 or more types of repeating units (1)-(3) each independently. Further, the liquid crystalline polyester may have a repeating unit other than the repeating units (1) to (3), but the content thereof is usually 10 mol% or less with respect to the total amount of all repeating units, preferably 5 mol% or less.

  The liquid crystalline polyester preferably has a repeating unit (3) in which X and Y are each an oxygen atom (having a repeating unit derived from a predetermined aromatic diol), since the melt viscosity tends to be low. As the repeating unit (3), it is more preferable that only X and Y are each an oxygen atom.

In addition, the liquid crystalline polyester includes, as essential constituents, Ar ¹ of the repeating unit (1) is 1,4-phenylene group, Ar ^{2 of the} repeating unit (2) is 1,4-phenylene group and 1,3-phenylene group. On the other hand, when Ar ³ of the repeating unit (3) contains a 4,4′-biphenylylene group, the strength and elastic modulus of the resulting fiber are excellent.

  Furthermore, when the content of the repeating unit containing a 2,6-naphthylene group is 40 mol% or more with respect to the total content of all the repeating units, the liquid crystalline polyester has electrical characteristics (low dielectric loss tangent) of the obtained fiber. Excellent.

In this case, as the repeating unit (1), those in which Ar ¹ is a 2,6-naphthylene group (repeating unit derived from 6-hydroxy-2-naphthoic acid) are the electrical characteristics (low dielectric loss tangent) of the resulting fiber. ) Is preferable.

As the repeating unit (2), Ar ² is a 2,6-naphthylene group (a repeating unit derived from 2,6-naphthalenedicarboxylic acid), and Ar ² is a 1,4-phenylene group. (Repeating unit derived from terephthalic acid) is preferable because it is excellent in electrical characteristics (low dielectric loss tangent) of the resulting fiber.

Furthermore, as the repeating unit (3), Ar ³ is a 1,4-phenylene group (repeating unit derived from hydroquinone), and Ar ³ is a 4,4′-biphenylylene group (4,4 ′ -A repeating unit derived from dihydroxybiphenyl) is preferable because it is excellent in the electrical properties (low dielectric loss tangent) of the resulting fiber.

Typical examples of liquid crystal polyester with high heat resistance and high melt tension are:
(I) The repeating unit (1) (repeating unit derived from 6-hydroxy-2-naphthoic acid) in which Ar ¹ is a 2,6-naphthylene group, preferably 40 moles with respect to the total amount of all repeating units. % To 74.8 mol%, more preferably 40 mol% to 64.5 mol%, still more preferably 50 mol% to 58 mol%,
(Ii) Ar ² is a 2,6-naphthylene group (2) (a repeating unit derived from 2,6-naphthalenedicarboxylic acid), preferably 12.5 mol% or more and 30 mol% or less, more preferably 17.5 mol% or more and 30 mol% or less, more preferably 20 mol% or more and 25 mol% or less,
(Iii) Ar ² is a 1,4-phenylene group repeating unit (2) (repeating unit derived from terephthalic acid), preferably 0.2 mol% or more and 15 mol% or less, more preferably 0.5 mol % To 12 mol%, more preferably 2 mol% to 10 mol%,
(Iv) The repeating unit (3) (repeating unit derived from hydroquinone) in which Ar ³ is a 1,4-phenylene group is preferably 12.5 mol% or more and 30 mol% or less, more preferably 17.5 mol%. 30 mol% or less, more preferably 20 mol% or more and 25 mol% or less, and
(V) the content of the repeating unit Ar ² is a 2,6-naphthylene group (2) are, Ar ² is a 2,6-naphthylene group repeating unit (2) and Ar ² is 1,4-phenylene group The total content of the repeating unit (2) is preferably 0.5 mol times or more, more preferably 0.6 mol times or more.

  In the liquid crystal polyester, the total amount of monomers having 2,6-naphthylene groups (the total amount of 6-hydroxy-2-naphthoic acid, 2,6-naphthalenedicarboxylic acid and 2,6-naphthalenediol) is the sum of all monomers. It can manufacture by superposing | polymerizing (polycondensation) so that it may become 40 mol% or more with respect to quantity.

  The liquid crystalline polyester can be produced by melt polymerizing raw material monomers corresponding to the repeating units constituting the liquid crystalline polyester and solid-phase polymerizing the obtained polymer (hereinafter sometimes referred to as “prepolymer”). preferable. Thereby, high molecular weight liquid crystal polyester having high heat resistance, strength and rigidity can be produced with good operability. Melt polymerization may be carried out in the presence of a catalyst. Examples of this catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, And nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine and 1-methylimidazole, and nitrogen-containing heterocyclic compounds are preferably used.

  The liquid crystalline polyester used as a raw material for the fiber production material has a flow initiation temperature of usually 280 ° C. or higher, preferably 280 ° C. or higher and 400 ° C. or lower, more preferably 280 ° C. or higher and 360 ° C. or lower. As the flow start temperature is higher, the heat resistance, strength, and rigidity are more likely to be improved. However, if the flow start temperature is too high, the melting temperature and the melt viscosity are likely to be high, and the fiber tends to be difficult to be formed.

Further, the liquid crystal polyester has a melt viscosity of 70 Pa · s or less measured at 360 ° C. under conditions of a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ using a flow characteristic tester. If the melt viscosity is greater than 70 Pa · s, the strength of the resulting fiber tends to decrease, and low molecular weight components tend to be difficult to reduce.

  The liquid crystalline polyester preferably has a melt viscosity of 40 Pa · s or less measured at 360 ° C. under the above conditions, and more preferably has a melt viscosity of 20 Pa · s or less measured at 360 ° C. under the above conditions. It is.

  Considering the long-term thermal stability of the liquid crystal polyester in fiberization, the liquid crystal polyester used preferably has a melt viscosity measured under the above conditions of 70 Pa · s or less at a temperature of 340 ° C., and the melt viscosity measured under the above conditions Is more preferably 340 ° C., and a temperature at which the melt viscosity measured under the above conditions is 20 Pa · s or less is more preferably 340 ° C.

  The melt viscosity was measured with respect to the value of the liquid crystalline polyester powder, which is a raw material of the fiber manufacturing material, and the fiber manufacturing material which was melt-kneaded using an extruder and formed into a pellet form as described later. There is almost no difference between the values. Therefore, it is good also as measuring about the pellet-form fiber manufacturing material with a simple measurement.

(Fiber manufacturing material)
The fiber manufacturing material of this embodiment can be prepared by melt-kneading the above-mentioned liquid crystalline polyester using an extruder. After melt-kneading, it is preferably formed into a pellet.

  The extruder preferably has a cylinder, one or more screws arranged in the cylinder, one or more supply ports provided in the cylinder, and one or more vent portions provided in the cylinder. Used. It is preferable to use an extruder provided with a kneading portion on the downstream side of the supply port (when a plurality of supply ports are provided, on the downstream side of each supply port, respectively). Here, the kneading portion refers to a portion that is provided in a part of the screw and efficiently performs melt-kneading. Examples of the kneading portion include a kneading disc (right kneading disc, neutral kneading disc, right kneading disc), a mixing screw, and the like.

  The fiber manufacturing material according to the present embodiment is obtained by connecting a decompression facility to a portion having one or more vent portions provided in a cylinder, and degassing the inside of the cylinder using the decompression facility during melt-kneading. It can be obtained by removing the remaining low molecular weight component from the tempered liquid crystal polyester and reducing the content.

The resulting fiber manufacturing material has a melt viscosity of 70 Pa · s or less measured at 360 ° C. under conditions of a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ using a flow characteristic tester. If the melt viscosity measured at 360 ° C. under the above conditions is greater than 70 Pa · s, the low molecular weight component tends to be difficult to reduce.

  According to the inventor's study, if the low molecular weight component remains in the liquid crystalline polyester used as the raw material for the fiber production material, the low molecular weight component is vaporized during melt kneading and during fiber production (spinning). It has been found that bubbles are formed inside. When forming molded products such as plates and housings using liquid crystal polyester, the size of such bubbles is sufficiently small relative to the thickness of the molded product, so that even if bubbles are present, the strength is increased. Hard to influence. However, when fibers are spun using liquid crystalline polyester, the bubbles are relatively large with respect to the size of the cross section of the fibers, and the fibers are easily broken from the positions of the bubbles. Since such bubbles are present in the obtained fiber, the obtained fiber has high strength in a portion where bubbles are not present and low strength in a portion where bubbles are present, resulting in variations in strength.

  On the other hand, since the fiber manufacturing material of the present embodiment is melt-kneaded while degassing, the low molecular weight component inside the liquid crystal polyester can be suitably reduced, which is attributable to the low molecular weight component as described above. Air bubbles are difficult to form. Therefore, the fiber is not easily broken due to the bubbles, and the occurrence of variation in strength is suppressed.

  In order to further reduce the low molecular weight component remaining in the liquid crystal polyester, it is preferable to degas using a vacuum equipment under a vacuum condition of 0.04 MPa or less, more preferably 0.03 MPa or less, and still more preferably. Is 0.02 MPa or less.

  Although it does not specifically limit about pressure reduction equipment, The pressure reduction of a vent part is normally performed using a pump, for example, a water seal pump, a rotary pump, and an oil diffusion pump. A turbo pump is mentioned.

  In the production of the material for fiber production, an extruder having two or more vent parts is used, a decompression equipment is connected to each vent part, and melt kneading while degassing from the two or more vent parts. It is preferable.

  Moreover, it is preferable to melt-knead using the extruder provided with the kneading part in the upstream of the vent part which connects decompression equipment.

(Fiber and fiber cloth made of liquid crystal polyester)
Next, a fiber obtained by spinning the fiber manufacturing material of the above-described embodiment and a fiber cloth (nonwoven fabric or the like) using the fiber will be described.

  The fiber of this embodiment is obtained by spinning the above-described fiber manufacturing material. Such a fiber can be obtained by fiberizing a fiber production material by a known method, for example, by melt spinning the fiber production material.

  When the fiber manufacturing material is made into fibers by melt spinning, the fiber manufacturing material is heated to a molten state, and the molten fiber manufacturing material is extruded through a predetermined nozzle while the fiber manufacturing material is stretched. By cooling and solidifying again, fibers in which the fiber manufacturing material is thinned can be obtained.

  At this time, if the fiber manufacturing material stretched by melt spinning is wound as it is, a liquid crystal polyester fiber can be obtained. On the other hand, before the fiber manufacturing material is completely solidified, a predetermined substrate is moved while moving the nozzle or the like. A fiber cloth (non-woven fabric) made of liquid crystal polyester fiber can be obtained by depositing the film on the surface.

  Since such a liquid crystal polyester fiber is obtained by spinning the fiber manufacturing material of the present embodiment described above, it can have a low dielectric loss and high heat resistance. In addition, liquid crystalline polyester, which is a raw material for fiber manufacturing materials, has high thermal stability that the viscosity is small even when melted for a long time, so that it can be easily made into fibers by melt spinning as described above. Since a low viscosity can be maintained, it is possible to form fine fibers.

  Therefore, the liquid crystal polyester fiber and the fiber cloth (nonwoven fabric) of this embodiment are easily fiberized, have a thin fiber diameter, and also maintain the excellent characteristics of the liquid crystal polyester such as low dielectric loss and high heat resistance. Therefore, it can be applied to various uses including electronic parts.

  According to the fiber manufacturing material having the above-described configuration, it is possible to reduce the amount of low molecular weight components by degassing during melt-kneading, and to reduce variations in fiber strength.

  Moreover, according to the liquid crystal polyester fiber of the above structure, it becomes the fiber which suppressed the dispersion | variation in fiber strength by using the above-mentioned material.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[Melt viscosity]
The melt viscosity is obtained by using a flow property tester (Capillograph) 1B manufactured by Toyo Machine Seisakusho Co., Ltd., with respect to each measurement temperature, with a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ . Measured under conditions.

[Flow start temperature]
The flow start temperature of the liquid crystalline polyester, which is the raw material for the fiber manufacturing material, was measured using a flow characteristic evaluation apparatus “Flow Tester CFT-500 type” manufactured by Shimadzu Corporation. About 2 g of a sample is filled in a capillary rheometer equipped with a die having an inner diameter of 1 mm and a length of 10 mm, and liquid crystalline polyester is pushed out from the nozzle at a heating rate of 4 ° C./min under a load of 9.8 MPa (100 kgf / cm ² ) The temperature at which the melt viscosity is 4800 Pa · s (48000 poise) was taken as the flow start temperature.

(Prepolymer synthesis)
To a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer and a reflux condenser, 911 g (6.6 mol) of p-hydroxybenzoic acid and 409 g (2.2 mol) of 4,4′-dihydroxybiphenyl were added. ), Isophthalic acid 91 g (0.55 mol), terephthalic acid 274 g (1.65 mol), and acetic anhydride 1235 g (12.1 mol) were added and stirred.
Next, 0.17 g of 1-methylimidazole was added as a catalyst, and after the inside of the reactor was sufficiently replaced with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream, and the temperature was maintained. Reflux for 1 hour.
Next, 1.7 g of 1-methylimidazole was added, and the temperature was raised to 320 ° C. over 2 hours and 50 minutes while distilling off the by-product acetic acid to be distilled off and unreacted acetic anhydride. The time at which an increase in torque was observed was regarded as the end of the reaction, and the contents were taken out to obtain a prepolymer powder (particle diameter of about 0.1 mm to about 1 mm). The flow starting temperature was 257 ° C.

<Synthesis Example 1>
The obtained prepolymer powder was heated from 25 ° C. to 250 ° C. over 1 hour, and then heated from 250 ° C. to 280 ° C. over 3 hours and 34 minutes. Then, it heat-retained at 280 degreeC for 5 hours, solid-phase-polymerized, and cooled, and powdery liquid crystalline polyester (A) -1 was obtained.
The flow starting temperature of the liquid crystal polyester (A) -1 was 330 ° C.

<Synthesis Example 2>
The obtained prepolymer powder was heated from 25 ° C. to 250 ° C. over 1 hour, and then heated from 250 ° C. to 270 ° C. over 2 hours and 23 minutes. Then, it kept at 270 degreeC for 5 hours, solid-phase-polymerized, and also cooled, and obtained powdery liquid crystalline polyester (A) -2.
The flow starting temperature of the liquid crystal polyester (A) -2 was 315 ° C.

<Synthesis Example 3>
The obtained prepolymer powder was heated from 25 ° C. to 250 ° C. over 1 hour, and then heated from 250 ° C. to 275 ° C. over 2 hours and 58 minutes. Then, it kept at 275 degreeC for 5 hours, solid-phase-polymerized, and also cooled, and obtained powdery liquid crystalline polyester (A) -3.
The flow starting temperature of the liquid crystal polyester (A) -3 was 320 ° C.

<Synthesis Example 4>
The obtained prepolymer powder was heated from 25 ° C. to 250 ° C. over 1 hour, and then heated from 250 ° C. to 277 ° C. over 3 hours and 13 minutes. Thereafter, the mixture was kept at 277 ° C. for 5 hours for solid phase polymerization, and further cooled to obtain a powdered liquid crystal polyester (A) -4.
The flow starting temperature of the liquid crystal polyester (A) -4 was 325 ° C.

<Example 1>
The liquid crystal polyester (A) -1 obtained in Synthesis Example 1 was melt-kneaded using a twin-screw extruder (PCM-30, manufactured by Ikegai Co., Ltd.) and granulated into pellets. The cylinder of the used extruder was provided with two vent parts, and each vent part was connected with a water ring pump and processed while being decompressed to 0.02 MPa by the water ring pump during melt kneading.

  When the melt viscosity of the obtained pellet was measured under the above conditions, it was 35 Pa · s at 350 ° C. As the inventor's knowledge, it has been found that there is no difference between the value measured for the liquid crystal polyester before melt kneading and the value measured for the pellet after melt kneading for the melt viscosity of the liquid crystal polyester. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature rises, when the melt temperature of liquid crystal polyester (A) -1 is measured at 360 ° C., the melt viscosity value is lower than 35 Pa · s, which is the above measurement result. Will be obtained. That is, it can be seen that the melt viscosity of liquid crystal polyester (A) -1 measured at 360 ° C. is 70 Pa · s or less.

  Next, using a multifilament spinning device “Polymer Mate V” manufactured by Chubu Chemical Machinery Co., Ltd., the molten material was passed through a filter (made of stainless steel), then discharged from a nozzle, and melt-spun at 350 ° C. The nozzle used had a hole diameter of 0.3 mm and 24 holes, and was wound up at a discharge rate of 25 g / min and a spinning speed of 400 m / min.

  The liquid crystal polyester fiber obtained after 10 minutes, 30 minutes and 1 hour from the start of discharge of the liquid crystal polyester fiber was sampled, and each sampled fiber was wound around a metal bobbin and heat-treated at 320 ° C. for 12 hours. The tensile strength (average value of five test pieces) of each heat treated yarn thus obtained was measured.

<Example 2>
About liquid crystalline polyester (A) -2, it pelletized similarly to Example 1 except having set the pressure reduction degree at the time of melt kneading to 0.04 MPa.
About the obtained pellet, when melt viscosity was measured on the said conditions, it was set to 15 Pa.s at 340 degreeC. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -2 is measured at 360 ° C., the melt viscosity value is lower than 15 Pa · s, which is the measurement result. Will be obtained. That is, it can be seen that the melt viscosity of liquid crystal polyester (A) -2 measured at 360 ° C. is 70 Pa · s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

<Example 3>
About liquid crystalline polyester (A) -3, it pelletized similarly to Example 1 except having set the pressure reduction degree at the time of melt kneading to 0.01 Mpa.
When the melt viscosity of the obtained pellet was measured under the above conditions, it was 16 Pa · s at 350 ° C. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -3 is measured at 360 ° C., the melt viscosity value is lower than 16 Pa · s, which is the measurement result. Will be obtained. That is, it turns out that the melt viscosity which measured liquid crystal polyester (A) -3 at 360 degreeC becomes 70 Pa * s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

<Example 4>
About liquid crystalline polyester (A) -4, it pelletized similarly to Example 1 except having set the pressure reduction degree at the time of melt kneading to 0.02 MPa.
When the melt viscosity of the obtained pellet was measured under the above conditions, it was 25 Pa · s at 350 ° C. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -4 is measured at 360 ° C., the melt viscosity value is lower than 25 Pa · s, which is the above measurement result. Will be obtained. That is, it can be seen that the melt viscosity of liquid crystal polyester (A) -4 measured at 360 ° C. is 70 Pa · s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

<Comparative Example 1>
Liquid crystal polyester (A) -1 was pelletized in the same manner as in Example 1 except that it was processed without decompression during melt kneading.
When the melt viscosity of the obtained pellet was measured under the above conditions, it was 22 Pa · s at 320 ° C. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -1 is measured at 360 ° C., the melt viscosity value is lower than 22 Pa · s, which is the above measurement result. Will be obtained. That is, it can be seen that the melt viscosity of liquid crystal polyester (A) -1 measured at 360 ° C. is 70 Pa · s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

<Comparative example 2>
About liquid crystalline polyester (A) -2, it pelletized like Example 1 except having processed without pressure reduction at the time of melt-kneading.
About the obtained pellet, when melt viscosity was measured on the said conditions, it was set to 15 Pa.s at 340 degreeC. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -2 is measured at 360 ° C., the melt viscosity value is lower than 15 Pa · s, which is the measurement result. Will be obtained. That is, it can be seen that the melt viscosity of liquid crystal polyester (A) -2 measured at 360 ° C. is 70 Pa · s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

<Comparative Example 3>
Liquid crystal polyester (A) -3 was pelletized in the same manner as in Example 1 except that it was processed without decompression during melt kneading.
When the melt viscosity of the obtained pellet was measured under the above conditions, it was 16 Pa · s at 350 ° C. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -3 is measured at 360 ° C., the melt viscosity value is lower than 16 Pa · s, which is the measurement result. Will be obtained. That is, it turns out that the melt viscosity which measured liquid crystal polyester (A) -3 at 360 degreeC becomes 70 Pa * s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

<Comparative example 4>
About liquid crystalline polyester (A) -4, it pelletized like Example 1 except having processed without pressure reduction at the time of melt-kneading.
When the melt viscosity of the obtained pellet was measured under the above conditions, it was 25 Pa · s at 350 ° C. Generally, since the melt viscosity of liquid crystal polyester decreases as the temperature decreases, when the melt temperature of liquid crystal polyester (A) -4 is measured at 360 ° C., the melt viscosity value is lower than 25 Pa · s, which is the above measurement result. Will be obtained. That is, it can be seen that the melt viscosity of liquid crystal polyester (A) -4 measured at 360 ° C. is 70 Pa · s or less.
Using the obtained pellets, spinning was carried out in the same manner as in Example 1.

  Table 1 below shows the measurement results of tensile strength and the dispersion (square of standard deviation) for the examples and comparative examples.

  First, as a result of the evaluation, in each of the examples and comparative examples, the liquid crystal polyester fibers could be stably spun without breakage of the liquid crystal polyester fibers for 1 hour from the start of discharge of the liquid crystal polyester fibers.

Moreover, about the tensile strength of the obtained fiber, about the fiber manufacturing material (Examples 1-4) obtained by degassing and melt-kneading under reduced pressure, it is obtained by melt-kneading without degassing. It was found that a fiber having a smaller dispersion and a uniform strength than that of the fiber manufacturing material (Comparative Examples 1 to 4) was obtained.
From these results, the usefulness of the present invention was confirmed.

Claims (8)

A fiber manufacturing material obtained by melt kneading while degassing using a liquid crystal polyester that satisfies the following requirements (a) and (b).
(A) Flow start temperature is 280 degreeC or more and 360 degrees C or less.
(B) Using a flow characteristic tester, the melt viscosity measured at 360 ° C. under a nozzle hole diameter of 0.5 mm and a shear rate of 1000 s ⁻¹ is 70 Pa · s or less. The said liquid-crystal polyester is a fiber manufacturing material of Claim 1 which has a repeating unit represented by following formula (1), following formula (2), and following formula (3).
(1) —O—Ar ¹ —CO—
(2) —CO—Ar ² —CO—
(3) ^-X-Ar 3 -Y-
(Ar ¹ represents a phenylene group, a naphthylene group, or a biphenylylene group. Ar ² and Ar ³ each independently represent a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4). X And Y each independently represents an oxygen atom or an imino group (—NH—), and each hydrogen atom in the group represented by Ar ¹ , Ar ² or Ar ³ is independently a halogen atom or a carbon number. (It may be substituted with an alkyl group of 1 to 10 or an aryl group of 6 to 20 carbon atoms.)
(4) -Ar ⁴ -Z-Ar ^5-
(Ar ⁴ and Ar ⁵ each independently represent a phenylene group or a naphthylene group. Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.) The liquid crystal polyester includes a repeating unit represented by the formula (1) in which Ar ¹ is a 1,4-phenylene group, and a formula (2) in which Ar ² is a 1,4-phenylene group or a 1,3-phenylene group. The fiber manufacturing material according to claim 2, comprising: a repeating unit represented by formula (3); and a repeating unit represented by formula (3) wherein Ar ³ is a 4,4′-biphenylylene group.   4. The fiber manufacturing material according to claim 2, wherein the liquid crystal polyester has a content of repeating units containing 2,6-naphthylene groups of 40 mol% or more based on a total content of all repeating units.   The fiber manufacturing material according to any one of claims 1 to 4, obtained by melt-kneading while degassing under a vacuum degree of 0.04 MPa or less.   The fiber manufacturing material according to any one of claims 1 to 5, which is obtained by melting and kneading while degassing from the two or more vent parts using an extruder having two or more vent parts.   The material for fiber production according to any one of claims 1 to 6, obtained by melt kneading while degassing from the vent portion using an extruder provided with a kneading portion on the upstream side of the vent portion.   A fiber obtained by spinning the fiber manufacturing material according to any one of claims 1 to 7.